These are two quotes from friends of mine; sound familiar?
First shop on-line, pick out your top three choices and call them on the phone. No live person or call center, forget about it.
The medium is the message here. You are not so much interested in exactly What they say, but How they respond. Are they evasive? Confused? Unresponsive? It all comes from the top, a good plumbing company or any company will have professionals on the front lines, especially taking calls from prospective new customers.
If your plumbing job is a bit complex, take photos of the damage on your phone on a regular basis (you may need for the record), such as when they snake out an upstairs sink and there is a flood on your kitchen ceiling.
If the plumbing company wants to overcharge or not pay for damages, tell them that you have downloaded a complaint form from the state licensing Board, such as the Virginia Department of and Professional and Occupational Regulation; they grant the license and can take it away and remind them of that; this is like magic.
Last, with ongoing problems and damage, your homeowner’s insurance may actually go to bat for you and even collect from the insurance company of the plumbing company, through what is called subrogation.